This invention relates generally to a new and useful locking connection for supporting grid systems such as those used to support ceiling tiles in suspended ceilings.
Such systems customarily comprise a plurality of parallel main tee members and a plurality of parallel cross tee members extending between the main tee members in right angular relation, the cross tees having locking connectors insertable through the main tees and typically interlocking therewith. In some systems, to provide increased resistance against unwanted separation, the locking connectors also interlock with each other as shown for example in U.S. Pat. No. 3,922,829.
Building codes in areas believed to be subject to seismic disturbances have been revised to require ever higher standards of performance under a variety of conditions subjecting such systems to forces tending to separate the grid members.
In addition, many installations require the integrity of the ceiling to be maintained for a predetermined period of time under elevated temperature conditions caused by fire.